1846.] Insects Injurious to Vegetation. 261 



have met with no report ever rendered by them. [Carey^s JV/w- 

 seum, vol. xi., p. 285.) 



At this time, as we infer from a clause in the circular just al- 

 luded to, and also from some passages in Dr. Mitchell's address 

 before the New York society of agriculture; (Transactions, vol. 

 i,, p. 32,) the insect was becoming so rare in all the more densely 

 settled parts of the middle states, which had been first overspread 

 by it, that it was the common opinion that it would soon vanish 

 from the country entirely. Notices of it in the magazines and 

 newspapers become more rare, and it was evidently ceasing to be re- 

 garded with that intense solicitude which it had hitherto excited. 

 It was, however, with unabated vigor, continuing its progress 

 southward. A letter from Prospect Hill, Delaware, dated June 

 12th, 1792, {Carey's Museum, vol. xi., p. 301,) states that the 

 fly arrived there " in prodigious clouds," about the middle of the 

 preceding September. It describes the place where the eggs were 

 deposited on the young wheat, the growth of the worm, and the 

 perishing of all the plants, except those growing upon a rich soil, 

 and adds further testimony in favor of the Underbill wheat. 



In 1797, Dr. Isaac Chapman, of Bucks county. Pa., prepared 

 one of the best accounts of this- species that has ever appeared, 

 containing the details of his own careful observations upon the 

 insect and the time of its appearance in its different stages. These 

 observations lead him to recommend as the most certain safe- 

 guards against the fall attack, late sowing, and against the spring 

 attack, a quick vigorous growth, to be obtained by procuring 

 southern seed and sowing it on a rich, elevated and dry soil. His 

 paper is published in the fifth volume of the Memoirs of the Phila- 

 delphia Society for Promoting Agriculture, a volume which M^e 

 regret having been unable to find in either of the largest libraries 

 of this state. We are therefore obliged to depend for its contents 

 upon second hand accounts. Dr. C. states that the fly was this 

 year found upon the west side of the Alleghany mountains. 



The eighth volume of the Encyclopedia Britannica, published 

 this year, gives (pages 489-495) an extended article under the 

 head Hessian Fly, consisting chiefly of a summary of the several 



